Sub-Nanoporous Battery Separator for Lithium Dendrite Suppression
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Solution Overview
Problem
Lithium metal batteries suffer from severe side reactions with the electrolyte and the formation of lithium dendrites, leading to a short cycle life due to the high reactivity of lithium metal and continuous loss of lithium.
Innovation Solution
A separator using a sub-nanoporous material with controlled pore sizes between 0.01 nm to 1 nm, incorporating metal-organic framework or molecular sieve materials, which confines the electrolyte within the pores, reducing side reactions and delaying dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as a negative electrode to increase energy density, then the energy density and operating voltage of the battery are improved, but the high reactivity of lithium metal causes severe side reactions with the electrolyte and formation of lithium dendrites, leading to short cycle life
Solution Approach 1:
A separator with sub-nanoporous structure (pore size 0.01-1 nm) filled with electrolyte is introduced as an intermediary between the lithium metal negative electrode and the bulk electrolyte. This separator mediates the interaction by confining electrolyte within its pores, which reduces side reactions between lithium metal and electrolyte, and delays lithium dendrite growth, thereby extending cycle life while maintaining high energy density
Solution Approach 2:
The separator employs a sub-nanoporous material structure with precisely controlled pore sizes (0.01-1 nm) that matches the size of solvent molecules in the electrolyte. This porous structure confines the electrolyte within the pores, creating a controlled interface that reduces harmful side reactions and dendrite formation, thus improving reliability without sacrificing the energy density benefits of lithium metal electrodes
2Reliability
If the pore size of the separator is reduced to confine electrolyte, then side reactions are reduced and cycle life is extended, but the manufacturing precision required to control pore sizes within 0.01 nm to 1 nm range increases
Solution Approach 1:
The invention specifies a particular pore size range (0.01-1 nm) for the separator material that optimizes the balance between electrolyte confinement effectiveness and manufacturing feasibility. This parameter selection enables sufficient electrolyte confinement to reduce side reactions and extend cycle life, while remaining within achievable manufacturing precision capabilities for sub-nanoporous material fabrication
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The separator improves safety performance and extends the cycle life of the electrochemical apparatus by confining the electrolyte, reducing side reactions, and increasing lithium deposition density, thereby enhancing lithium-ion transference and maintaining high energy density.
Implementation Method 1
the pore size of pores of the sub-nanoporous material is greater than or equal to the size of the solvent molecules, which facilitates confinement of the electrolyte within the pores of the sub-nanoporous material
Implementation Method 2
a pore size of pores of the sub-nanoporous material ranges from 0.01 nm to 1 nm... facilitates confinement of the electrolyte within the pores... reduces side reactions between lithium metal and the electrolyte
Data Source
AI summary
A separator includes a sub-nanoporous material and a binder, where the sub-nanoporous material includes a metal-organic framework material or a molecular sieve material, and a pore size of pores of the sub-nanoporous material ranges from 0.01 nm to 1 nm. The separator can confine an electrolyte within the pores of the sub-nanoporous material. Applying the separator to an electrochemical apparatus facilitates reduction of side reactions between lithium metal and the electrolyte during cycling of the electrochemical apparatus, and increases lithium deposition density on a surface of a negative electrode plate, thereby alleviating issues such as cracking and peeling of an SEI film during cycling; and further facilitates an increase in lithium-ion transference number, thereby delaying growth of lithium dendrites, improving safety performance of the electrochemical apparatus, and extending the cycle life of the electrochemical apparatus.